Airbag Diffuser Mechanism for Occupant Restraint Control

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Solution Overview

Problem

Front airbag devices, such as driver and passenger-side airbags, face challenges in deploying effectively when occupants are close to the steering wheel or instrument panel, leading to inadequate restraint and increased damage due to insufficient space and delayed deployment.

Innovation Solution

An airbag device with a diffuser mechanism that controls the flow of expansion gas using a receiving surface and band-like connecting members, allowing for controlled deployment direction and area, ensuring quick and wide restraint of occupants, even when seated close to the airbag deployment point.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the airbag is deployed quickly to restrain the occupant, then the occupant protection performance is improved, but the occupant may be damaged significantly when seated close to the steering wheel

Engineering Contradiction:

Improveairbag deployment speedVSAvoidoccupant damage

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

The airbag is designed with non-uniform thickness, having a first thickness in a first region and a second thickness in a second region, where the thickness ratio between the first and second regions is within a specific range. This local quality variation allows the airbag to provide different levels of protection and restraint force in different areas, reducing the risk of occupant damage while maintaining effective restraint.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the physical parameter of airbag thickness by creating a multi-layer structure with different thicknesses in different regions. The thickness ratio control allows optimization of the airbag's mechanical properties, balancing the restraint force with the risk of occupant injury.

Inventive Principle:

Principle #35Parameter changes

2Length of moving object

If the driver is seated close to the steering wheel, then the space between the steering wheel and driver is reduced, but the airbag cannot spread quickly in a plane parallel to the steering wheel

Engineering Contradiction:

Improvedistance between steering wheel and driverVSAvoidairbag spreading speed

Core Design Contradiction:

Length of moving objectVSSpeed

Solution Approach 1:

The airbag incorporates a thinning portion in the region facing the steering wheel, creating a local area with reduced thickness. This allows the airbag to expand more quickly in the direction parallel to the steering wheel, ensuring rapid coverage even when the driver is seated close, while other regions maintain sufficient thickness for effective restraint.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent addresses the two-dimensional expansion problem by varying the thickness dimension (third dimension) of the airbag. By creating a multi-layer structure with different thicknesses, the airbag achieves faster expansion in specific directions while maintaining overall structural integrity and restraint capability.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Ease of manufacture

If the airbag is designed with uniform thickness, then the manufacturing is simplified, but the occupant restraining performance is insufficient when occupant position varies

Engineering Contradiction:

Improveairbag manufacturing simplicityVSAvoidoccupant restraining performance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The airbag is designed with different thicknesses in different regions to adapt to varying occupant positions and sizes. The thinning portion facing the steering wheel and the multi-layer structure with controlled thickness ratios allow the airbag to provide optimized restraint force for drivers seated at different distances, improving reliability while maintaining manufacturability through a systematic multi-layer design.

Inventive Principle:

Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The diffuser mechanism enables rapid and effective deployment of the airbag in a planar direction, minimizing damage to occupants by ensuring timely and wide restraint of the chest and abdomen, while adjusting gas flow to optimize deployment shape and behavior.

Implementation Method 1

a gas generator that generates expansion gas

Methodology Applied

Scientific EffectGas generation:

Implementation Method 2

a diffuser disposed inside the airbag to control a flow of the expansion gas

Methodology Applied

Scientific EffectGas flow control:

Data Source

PatentUS11235731B2Airbag device

Publication Date: 2022.02.01 AUTOLIV DEV AB

AI summary

[Object]. An object is to suitably control the deployment shape of an airbag, thereby improving the occupant restraining performance. Another object is to reduce damage to an occupant located close to a steering wheel or an instrument panel.[Solving Means]. An airbag device according to the present invention includes: a gas generator that generates expansion gas; an airbag that expands and deploys due to the expansion gas to restrain an occupant; and a diffuser disposed inside the airbag to control a flow of the expansion gas. Given that a direction toward the occupant is a first direction, the diffuser includes a receiving surface disposed between the gas generator and the airbag in the first direction to receive the expansion gas discharged from the gas generator; and a plurality of band-like connecting members having one end connected to an edge of the receiving surface and the other end directly or indirectly connected to the gas generator.